Buying immediately can make sense if you already know the city, your job is stable and you have a strong pre-approval in hand, since paying rent twice, once on temporary lodging and once on a mortgage you are not living in yet, adds real cost for no benefit.
Temporary lodging costs money too, so the comparison is not free versus paid, it is a few months of rent against the risk of choosing the wrong neighbourhood or house under time pressure. A short stay also lets you test a commute and a winter before committing.
The right answer depends on how well you already know Saskatoon and how firm your timeline actually is, not a general rule. Get your hand-reviewed valuation from Joel Dyck.